Development of timber - concrete composite bridge decks in Brazil

This paper reports on an evaluation of the behavior of X-shaped shear connectors for timber-concrete composite bridge decks. Direct shear tests of the connectors, which were subjected to a total of 2 x 106 load cycles, indicated that their ultimate capacity was not affected by the fatigue cycles and that accumulated fatigue damage was the result of an initial slip that tended to stabilise after 1 x 106 cycles. Three composite girders with Tshaped cross section were loaded to failure after being subjected to 1 x 106 cycles. The test results indicated that the X-shaped connection conferred high resistance and stiffness on the composite system, offering an excellent alternative for composite bridge decks. To conclude, details of the design and load testing of a 7m span composite bridge in Brazil are presented and the test results are compared with those of a timber bridge, confirming the advantages of the composite system.